3D printing is a technology based on mathematical model files, using adhesive materials, such as special wax, powdered metal or plastic materials, applying a layer-by-layer printing method to construct an object. It is different from a traditional material construction method, and is a new three dimensional layer-by-layer printing method via gradually adding materials. With the rapid development of 3D printing technology, laser technology, due to its speed and accuracy, has been widely applied to 3D printing as the source of energy. Specifically, photosensitive resin stereolithography apparatus (SLA) has dominated the market. SLA uses the principle of three dimensional sculpture, a resin tank is filled with liquid photosensitive resin, and the photosensitive resin is cured after a fast UV laser irradiation to directly obtain a cured resin or similar plastic product.
The design and optimization of the optical system of a laser 3D printer directly affects the printing precision, speed, and stability. For example, CN104228068A discloses a rapid SLA 3D printer and a printing method using thereof. In this 3D printer, a lifting station above a vertical slot can only move up and down, and the angle of the lifting station cannot be adjusted automatically based on the changes of the angle of the resin surface in a resin tank. Thus, when the resin surface angle in the resin tank is an inclined angle, the lifting station and the resin surface will not have a good fit. To achieve optimized printing results, workers will manually adjust the angle of the lifting station after printing one layer based on the inclined angle of the resin surface. It not only is time consuming, but also affects printing quality, not meeting printing precision, speed, and, and product stability requirements. Especially for high-end applications, such as modeling jewelry, dental tooth mold, prototype models, the printing needs cannot be met.